2191894717 has 4 divisors (see below), whose sum is σ = 2192718016. Its totient is φ = 2191071420.

The previous prime is 2191894699. The next prime is 2191894721. The reversal of 2191894717 is 7174981912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2191894717 - 2¹¹ = 2191892669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191844717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407643 + ... + 412984.

It is an arithmetic number, because the mean of its divisors is an integer number (548179504).

Almost surely, 2^2191894717 is an apocalyptic number.

It is an amenable number.

2191894717 is a deficient number, since it is larger than the sum of its proper divisors (823299).

2191894717 is an equidigital number, since it uses as much as digits as its factorization.

2191894717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823298.

The product of its digits is 254016, while the sum is 49.

The square root of 2191894717 is about 46817.6752626612. The cubic root of 2191894717 is about 1298.9922598455.

The spelling of 2191894717 in words is "two billion, one hundred ninety-one million, eight hundred ninety-four thousand, seven hundred seventeen".